Two 90-minute instalments by the Boys From The Blackstuff writer will tell the true story of what became known as The Laconia Incident.
The British vessel was sunk by a German U-Boat in September 1942, only for the commander of the submarine to realise that the Laconia was carrying thousands of civilians and Italian prisoners of war.
Defying Nazi orders, Lt Commander Werner Hartenstein attempted to rescue the survivors with his U-Boat. Events took another terrible twist when the pilot of a B-24 bomber, under orders to sink submarines, failed to identify Hartenstein's Red Cross flags.
"Laconia is a powerful and compelling story and we're delighted to be bringing it to BBC Two, along with the esteemed storytelling talents of Alan Bleasdale," said Jane Tranter, the BBC's controller of fiction.
Filming will begin in Germany and Malta in the autumn for transmission next year.